Tower supporting insulator



July 21', 1936. HAwLEY "2,048,504

TOWER SUPPORTING INSULATOR Original Filed March 25, 9

llllll' Patented July 21, 1936 UNITED STATES PATENT OFFICE 2,048,504 TOWER SUPPORTING INSULATOB Original application March 25, 1929, Serial No.

Divided and this application September 28, 1932, Serial No. 635,259

4 Claims.

This application is a division of my allowed application for patent for Tower and strain insulators, filed March 25th, 1929 and given Serial No. 349,802. a

The invention relates to insulators, particularly those ofthe strain type, that is to say in which the dielectric material is compressed, and has special reference to .means for mounting or supporting a radio tower, transmission line supporting tower, or other similar structural steel or other metallic support intended to be insulated from the ground.

The principal object of the invention, generally stated, is to provide an insulator which may be mounted to support the leg or legs of a structural steel or other tower, one or more insulators of course for each leg of the tower, the construction of the insulator being such that all strains coming upon it will be compressive and never tensional.

Another object of the invention is to provide an insulator embodying a single dielectric member, preferably of porcelain, peculiarly shaped and combined with an arrangement of cooperating metallic elements which will insure great electrical as well as mechanical strength in addition to thermal efiiciency.

A further object of the invention is to provide a tower supporting or equivalent insulator in which the peculiarly shaped dielectric body is of hollow formation to enable advantage to be taken of the insulating properties of air.

, A further object is to provide an insulator of this type and for the above stated or analogous purposes which will be simple, inexpensive to make, efficient and durable in service, and a general improvement inthe art.

, To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in which:

Figure 1 is a view partly in side elevation and partly in longitudinal section showing the insulator mounted in place for supporting a leg of a structural steel tower,

Figure2 is a cross sectional view taken on line 22 of Figure 1 looking down,

Figure3 is a fragmentary detail perspective view showing the corner construction whereby the tower leg is secured upon the insulator.

' Referring more particularly to the drawing, it

the

will be seen that I have shown only a portion of a structural steel tower, in fact only one lower corner or leg, this being entirely sufficient for disclosure purposes as it will naturally be understood that the construction to be described should .5 be duplicated at each leg or corner, regardless of the number thereof.

Referring to the drawing in detail, the reference character I designates one of the upright legs and 22 represents a pair of horizontal members suitably secured to the leg as by rivets 3, bolts or the like. Naturally a tower necessarily consists of numerous other elements but such are not shown as it is only the lower corner construction or leg mounting, with insulating means therefor, which constitutes the subject matter of the present application. In the ordinary type of construction where it is not necessary or desirable that the tower be insulated from the ground, the upright legs are embedded in cement foundations or are bolted to suitable anchor elements so embedded.- However, in accordance with the present invention the tower is to be insulated while at the sametime it must be rigidly supported so as to have the necessary mechanical strength.

In carrying the principles of the invention into active practice, I preferably provide a cement, masonry or other similar foundation 4 which may have a substantial portion beneath the surface of the ground but which is here represented as extending above the surface to a material extent. Embedded or otherwise anchored within or to the foundation or foundations 4 are structural steel elements 5 here represented as of channel formation, and. these serve as supporting means for the insulator structure 6 to be described which is interposed between the foundation construction and each corner of the tower.

} Inthe present instance this insulator is shown as comprising a dielectric body 1, preferably of porcelain-formed, glazed and fired in the usual manner. This body I must have considerable strength for which reason I havedisclosed it as of double frusto-conical shape, that is to say it has its largest diameter at the center with both ends tapering off, the body being, moreover, preferably circular in cross section throughout so that the strains coming upon it will be uniform. The body is likewise shown as of shell-like form or hollow andthe thickness of the wall will of course vary in accordance with the other dimensions all of which would be governed by the "demands of the particular installation. Surrounding the central or largest part of this body is a metallic member 8 including a ring or band portion 9 and outstanding flanges l thereon. The band portion is shown as secured upon the dielectric body by cement H and, in accordance with well established insulator practice, the exterior of the porcelain body may be sanded or roughened at the area engaged by the cement so as to increase the holding power thereof. The flanges l0 are supported upon the metallic elements and are shown as secured thereto by bolts l2 equipped with nuts [3, the flanges being necessarily apertured at M for the passage of the bolts.

The ends of the dielectric body are open and carry upper and lower caps l5 and I6 which may be identical in construction, which constitute closures for the ends, and which are preferably held by cement I! applied in a well known manner. The end portions of the body may also be roughened or sanded to give the cement a better grip. Extending axially of the body is a bolt or rod 18 which preferably has both ends threaded and projecting considerably beyond the caps I5 and IS, the threaded ends carrying nuts I9 and 20 located, respectively, adjacent the caps l5 and 16.

For actually connecting the tower leg with the insulator 6, use may be made of an angular bracket member 2! located within the angle of the leg and secured thereto and to the transverse members 2 by means of the above described rivets 3. This bracket member is provided in its bottom flange 22 with a hole 23 for the passage of the bolt or threaded rod Hi.

In the use of the above described insulator in tower construction, the insulator itself may first be mounted upon the foundation members 4 and the tower leg then applied, or the tower leg may be held elevated and the insulator placed in position beneath it. The sequence of assembly of the parts is rather immaterial and will be governed by circumstances, size of parts, etc. Begardless of this detail, it is apparent that when the bolt or threaded rod I8 is in place extending through the hole 23 and when the nuts l9 and 23 are tightened, the tower leg will be rigid with respect to the insulator and the foundation members will carry the same. This construction is duplicated at each leg and it will be clear that the tower will be thus insulated from the ground.

From the foregoing description and a study of the drawing it will be apparent that I have thus provided a simple and yet highly efficient strain insulator per se and tower construction whereby structural steel radio, transmission line supporting and other towers may be insulated from the ground. The structure is easy to build and should have great mechanical strength and durability.

The structure possesses particular advantage from an electrical viewpoint. It should be remembered that while, this type of insulator is adapted for low frequency power purposes, it is designed specially for radio work. The porcelain is made as a double cone rather than as a straight or cylindrical tube, or other shape, in order to obtain a large air space between the bolt or rod and the inside surface of the porcelain body. This air space is the true insulator and will carry most of the voltage up to the time that it becomes over-stressed and is short circuited by a corona, whereupon the porcelain will become the major insulator. It is important that the air should be the principal insulator when working with radio frequencies as the energy loss will be proportional to the distance of the rod from the supporting base and proportional to the specific inductive capacities, or in other words the 5 dielectric constants of the insulating media. The air being the true insulator, rather than the porcelain, has a specific inductive capacity of unity whereas that of the porcelain is approximately five. In using an insulator of this char- 10 acter, design or shape, rather than one of a cylindrical or other shape, the power loss due to induction between parts will be the minimum.

While I have shown and described the preferred embodiment of the invention, it should be understood that the disclosure is merely an exemplification of the principles involved as the right is reserved to make all such changes in the details of construction as will widen the field of utility and increase the adaptability of the device provided such changes constitute no departure from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. Means for supporting and insulating from the ground a leg of a structural steel tower, comprising a foundation anchored to the ground, a. bracket secured to the leg of the structural steel tower, a vertically arranged insulator formed. as a single integral double ended hollow cone of dielectric material having its maximum diameter at the center and having its ends open, a metallic member embracing and secured to the exterior only of said dielectric member at the portion of maximum diameter thereof and secured to the foundation, metallic caps secured upon and closing the ends of said dielectric member, and a tie bolt extending axially of said hollow member and through the centers of said caps, and through said bracket, and nuts on the respective ends of said tie bolt for engagement with the lower cap and said bracket respectively.

2. A radio tower supporting and insulating means comprising a foundation anchored to the ground, metallic members carried by the foundation, an insulator arranged in upright position beneath a leg of the tower and formed as a single continuous hollow body of dielectric material of double cone shape having its maximum diameter at substantially the center and tapering toward both ends, a metal ring embracing and secured to the maximum diameter portion of said dielectric body entirely exteriorly thereof, means for securing said ring to the metallic members mounted on the foundation, metal caps secured upon and closing the ends of the dielectric body, and tie means passing axially through the dielectric body and connected with the tower leg whereby upward and downward strains exerted by the tower leg will apply only compressive force to the dielectric body.

3. A radio tower supporting and insulating means comprising a foundation anchored to the ground, metallic members carried by the foundation, an insulator arranged in upright position beneath a leg of the tower and formed as a single continuous hollow body of dielectric material of double cone shape having its maximum diameter at substantially the center and tapering toward both ends, a metal ring embracing and secured T0 to the maximum diameter portion of said dielectric body entirely exteriorly thereof, means for securing said ring to the metallic members mounted on the foundation, metal caps secured upon and closing the ends of the dielectric body,

and tie means passing axially through the dielectric body and connected with the tower leg whereby upward and downward strains exerted by the tower leg will apply only compressive force to the dielectric body, the lower edge of the ring embracing the dielectric body being of less diameter than the maximum diameter of the body.

4. Means for supporting and insulating from the ground a leg of a structural steel tower, comprising a foundation anchored to the ground, a vertically arranged insulator of hollow form, a metallic member embracing and secured only to the exterior of the insulator at the intermediate portion thereof and designed for mounting upon the foundation, closure members upon the ends of the insulator, and tie means passing axially through the insulator and connected with the tower leg whereby upward and downward strains exerted by the tower leg will apply only compressive force to the insulator, the wall of the insulator being continuous and unbroken and interposed between said metallic member and said tie means for reducing current leakage between 10 the metallic member and the tie means.

KENT A. HAWLEY. 

